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8 Signs Of Not Eating Enough For Weight Loss

Michael Garrico
Published by Michael Garrico | Co-Founder & Marketing Director
Last updated: August 5, 2023

Some people trying to lose weight restrict their calorie consumption too much, causing them more harm than good and actually slowing down their weight loss.

I always advise my clients to eat nutritiously balanced meals and keep tabs on their bodies.

To help them better grasp this, I spent days researching the negative signs people should be able to recognize while on calorie restriction.

I discussed my findings with a registered dietician to show you how to tell if you're not eating enough food for weight loss.

Quick Summary

  • Mental fog, food cravings, unstable mood, insomnia, digestive issues, and energy dips are some signs you are not eating enough for weight loss.
  • You can improve your calorie intake by consistently eating healthy fats, complex carbs, and high protein.
  • Eating enough calories is healthy for your metabolisms, and it also supports different physiological activities.

8 Signs and Symptoms You're Eating Too Little to Lose Weight

Eating low carb diet food

1. Mental Fog

The first sign you're taking in too few calories is difficulty focusing on your workout.

Research suggests that brain cells rely on glucose as fuel for everyday activity [1].

Allowing your sugar levels to drop too low can result in poor cognitive performance and negatively impact your weight loss efforts.

2. Food Cravings

Your next sign that you are on a calorie deficit is that you are constantly thinking about food.

Research has shown that eating less increases food desires which can cause you to gain weight [2].

Furthermore, prolonging calorie restriction may reduce overall food cravings but increase the need for a specific type of food [3].

3. Insomnia

A person struggling to sleep

The third sign that you have a low caloric intake is you have trouble falling and staying asleep.

According to a study, not getting enough nutrients affects the production of brain chemicals and hormones that influence sleep and wakefulness, resulting in sleep disturbances [4].

When you continuously restrict calories and sleep poorly, your metabolism slows down.

4. Unstable Mood

Another sign that you are in a caloric deficit is that you are often cranky over trivial matters.

Research suggests that deficiencies in nutrition, particularly cobalamin, folate, and zinc, can cause you to lose your temper and experience mood swings [5].

During these times, stress hormones can increase, affecting your eating habits adversely.

5.Energy Dips

Tired and exhausted woman with not enough energy

The next sign that you’re not taking in too many calories is less energy expenditure.

According to studies, a lack of B vitamins, iron, and zinc impairs your body's physiological processes, including energy metabolism [6].

Having your metabolic process compromised can lead to feeling tired most of the time, which can take a toll on your workout performance.

6. Digestive Issues

Another sign of under-eating is having issues in your digestive tract.

According to research, a lack of nutrients such as essential amino acids, the building blocks of protein, can cause inflammation to the small intestines, resulting in indigestion, poor absorption, and compromising overall health [7].

“Your body needs a certain amount of calories just to sustain proper function.”

- Kimberly Lummus, MS, RD

7. Low Immunity

A woman with low immunity and coughing

One more sign of getting fewer calories is a weak resistance to infection.

Researchers have found that a lack of vitamins and minerals increases the risk of chronic diseases like hypertension and elevated blood sugar levels, which can negatively influence physical performance [8].

8. Muscle Loss

The final sign that you’re severely cutting calories for fat loss is that you’re losing muscle mass.

Research shows that muscle mass loss is more likely to happen if the calorie-restricted diet is low in protein and is not supplemented with regular exercise [9] [10].

If you keep losing more muscles, you might not be able to lose weight in the long run.

How Can You Improve Your Calorie Intake?

You can improve your calorie intake by consistently eating foods high in protein, complex carbs, and healthy fats.

By choosing healthy foods and consuming them in tiny portions throughout the day, you can get all the nutrients your body needs without gaining weight.

You can add avocado slices to your sandwich, sprinkle healthy nuts on your sugar-free ice cream, or make an egg white omelet with low-fat cheese and lots of veggies.

What Are the Potential Benefits of Eating Enough Calories?

A woman smiling while eating healthy vegetable meal

One of the potential benefits of eating enough calories is a healthy metabolism, which supports proper physiological activities of the body.

Research shows that our bodies need extra calories to properly digest and absorb the food we eat [11].

Through these processes, our bodies are able to get enough energy.

This energy is necessary for us to perform basic functions like breathing and walking. It also keeps us healthy by allowing our cells to keep regenerating and growing.

Are There Risks to Eating Too Few Calories?

Close up image of a woman giving a spoonful of green food

Aside from the signs and symptoms of eating too few calories, the greater risks include having difficulty meeting your daily nutritional needs.

Diets that are calorie-restricted may not provide you with sufficient amounts of nutrients such as carbs, fats, proteins, minerals, and vitamins.

A lack of these essential nutrients can result in many health problems, which include anemia, osteoporosis, heart diseases, and autoimmune disorders [12]

Also, chronically depriving your body of enough calories may actually cause your basal metabolic rate to go down, which can make it even more difficult to lose weight [13].

The body simply adjusts to what it perceives as scarcity of food, and that leads to less calorie burning and less energy, which in turn makes working out even a bigger challenge.

So, you should keep in mind that, past a certain point, restricting calories becomes counterproductive for your weight loss, which is the very reason for restricting calories in the first place.


How Many Calories Is Too Little?

A daily intake of fewer than 1200 calories appears to be too little.

According to research, most adults require approximately 1,200 to 1,920 calories to maintain metabolism, muscle function, and brain activity [14].

Furthermore, an intake of fewer than 600 calories per day can put you in starvation mode.

What Happens if You Eat Too Few Calories and Work Out?

When you eat too few calories and work out, you can slow down your metabolism, reduce your overall well-being, and prevent yourself from losing any more weight.

A common rule is that people should consume at least 1,200 calories per day to keep a healthy weight.

People who engage in fitness routines, therefore, require more calories for more energy.

Can Eating Too Little Stop You From Losing Weight?

Eating too little can stop you from losing weight because it slows down your metabolism and limits the conversion of fat stores into energy.

This is why I always tell my clients to eat healthy snacks like fruit, yogurt, and nuts.

I often advise them to add natural fat burners into the mix to boost their efforts: 

We have tried and tested these products ourselves, and they have helped my clients increase the rate of fat loss and keep cravings in check without negatively affecting metabolism.


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